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A055665 Number of Eisenstein-Jacobi primes of successive norms (indexed by A055664). 2
6, 6, 12, 12, 12, 6, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 6, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 6, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 6, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

These are the primes in the ring of integers a+b*omega, a and b rational integers, omega = (1+sqrt(-3))/2.

REFERENCES

R. K. Guy, Unsolved Problems in Number Theory, A16.

L. W. Reid, The Elements of the Theory of Algebraic Numbers, MacMillan, NY, 1910, see Chap. VI.

FORMULA

a(n) = 6 * A055666(n) - Frank Adams-Watters (FrankTAW(AT)Netscape.net), May 05 2006

EXAMPLE

There are 6 Eisenstein-Jacobi primes of norm 3, omega-omega^2 times one of the 6 units [ +-1, +-omega, +-omega^2 ] but only one up to equivalence.

CROSSREFS

Cf. A055664-A055668, A055025-A055029. See A004016 and A035019 for theta series of Eisenstein (or hexagonal) lattice.

Sequence in context: A205029 A124508 A028317 * A168328 A176569 A127402

Adjacent sequences:  A055662 A055663 A055664 * A055666 A055667 A055668

KEYWORD

nonn,easy,nice

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Jun 09 2000

EXTENSIONS

More terms from Frank Adams-Watters (FrankTAW(AT)Netscape.net), May 05 2006

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Last modified February 16 09:27 EST 2012. Contains 205904 sequences.